The present invention relates to a heating apparatus used in a vacuum coffee maker, an electric pot for boiling water, and the like.
In a conventional heating apparatus for the electric pot and the like, provisions are provided for switching between the high temperature heating state corresponding to a boiling mode and the low temperature heating state corresponding to a warming mode. There are two ways to accomplish this operation. One way is to use two thermostats having different actuating temperature each other, and another way is to use a thermistor for detecting the temperature of a subject to be heated and a temperature control circuit for changing a setting temperature of the thermistor. The former way can achieve its objective more easily, but this method has its drawbacks in that the reliability of the product is lower due to its many mechanically moving parts. Also, the product's temperature hunting is larger and fine temperature control is extremely difficult to achieve. The latter way solves such drawbacks mentioned above, but this method has other problems in that the construction of the temperature control circuit is complicated, and the number of electronic components are required, which increases the cost and the difficulty of service.